Organic compositions having antiwear properties



United States Patent County, Pa., assignors to Mobil Oil Corporation, a corporation of New York No Drawing. Filed Sept. 20, 1966, Ser. No. U.S.- Cl. 252---32.7 Int. Cl. Cm 1/48 580,604 '12 Claims ABSTRACT OF THE DISCLOSURE Thisinvention relates to novelfcompositions having antiwear properties. In particular, this invention relates to organic fluids containing additives which 'provideen:

hanced antiwear properties thereto.

The metal surfaces of machinery or engines operating under heavy load wherein metal slides against metal, such as bearings, may undergo excessive wear or corrosion. Often the lubricants for such operations cannot prevent wear and-corrosion of the metal and, as a resu-lt the performance of the machine suffers. Lubricating oils have been blended with additives to increase the antiwear-- properties, however they have not always provided satis ice zinc, mercury, silver; lead, tin, chromium, cadmium, cobalt or nickel. M may also be the anhydride form of the diorganophosphorodithioic acid. The organic portion may be methyl, ethyl, proyl,

iso-propyl, butyl, t-butyl, pentyl, neopentyl, phenyl, toluyl and the like.

The phosophorodithioate compounds are generally produced by initially reacting an alcohol or a phenol with phosphorus pentasul-fide. This preparation is well known in the art. Two different alcohols may be used and therefore R, as defined above, may consist of different radicals. The resulting diorganophosphorodithioic acid or its anhydride form may be used in this invention. To produce the metal salts, the phosphorodithioic acid may be reacted with ammonia to form an ammonium phosphorodithioate intermediate. This intermediate may then be reacted with a metal halide to produce the desired metal salt. The salt precipitates out of the reaction mixture and may be isolated therefrom by the usual means of separation. This method of producing the metal salts of this invention is preferred, although the invention is not limited to a specific synthesis.

The activating co-additives of this invention are oxygennitrogenor boron-containing organic compounds. The preferred classes are (l) cyclic oxy, hydroxy or hydrazine compounds or (2) organoammonium borohydrides,

wherein the organic portion contains at least 4 carbon 7 atoms, and preferably from 4 to 40-.

factory protection. Lubricating compositions having im- I proved antiwear properties are of primary consideration for such performance.

It is an-objectof this invention to provide organic fluids having-improved antiwear properties. Another object of this invention is to provide lubricating compositions which can prevent undue wear of metal surfaces.

These and other objects are's'atisfied by novel fluid "compositions contaiiiiiig a majo'fpor'tioii of an" organic fluid and a'min'or portion sufficient to provide such fluids with enhanced antiwear characteristics 'ofaiiKhQ-fliorganophosphorodithioatecompound and an'organic activating co additiv' containing'oxyg'en or nitrogen or boron.

.invent'ion hasthe following structure:

" The diorganophosphorodithioate compound used in this "The cyclic co-additives of this invention have the general structure:

' R',,[Ar]X wherein Ar may be phenylene or naphthylene; X may be, -OH or -NHN'H R may be alkyl, aryl, alkaryl and 'aralkyl each containing from 1 to about 30 carbon atoms; m may be 1 or 2 and n may range from 0 to 5 (when n is O, the nucleus contains the normal hydrogen atoms). The cyclic oxy co-additive may also be a quinone. Thus'the co-additives of this invention include quinones, hydroquinones, phenols, napthols, phenylene diols, naphthalene diols, phenyl hydrazines, naphthyl hydrazines and substituted derivatives theerof. The organic substituents on the aromatic nucleus may range from methyl to eicosyl and may completely fill the available positions on the said nucleus. These aromatic compounds may be obtained by known methods and many are commercial prearations.

The organoammonium borohydrides useful in this invention include compounds of the structure:

wherein R" is alkyl, or aryl having from 1 to 20 carbon atoms and may be the same or different. Preferred of this .cla'ss is cetyltrimethylammonium borohydride. These wherein R may be alkyl, alkylene, cycloalkyl, aralkyl, i'

of M, Of the suitablemetals, M may preferably be copper,

compounds may also be prepared by known commercial methods.

' The additive combination of this invention may be present in the organic media at concentrations ranging from 0.05% to about 10% by weight of the total composition. The diorganophosphorodithioate is preferably present with respect to the activating agent in a weight ratio of from about 1:1 to about '821. The phosphorodithioates may themselves provide some antiwear properties, how- 3 4 ever, it has been found in accordance with the discovery 7 test lasted for hours. Cetane (n-hexadecane) was used of this invention that the presence of the co-additive inas the base fluid. creases the antiwear properties to an extent greater than After the test was completed in each case the pin was that provided by each of the components alone. In fact, examined to measure the wear scar diameter. The wear several of these metal salts provide little or no improverate is in terms of volume per travel distance (cc/cm.) ment in antiwear activity of the base fluid. Yet with the and was determined from the scar diameter. The coefficient addition of a small amount of the co-additive, the antiof friction was also calculated. When cetane was tested wear properties are exceptional. This surprising result is alone, with no additives at all, the wear rate was believed to be a synergistic cooperation between the two 25,000X10 cc./cm., and the coefiicient of friction was additives. 10 about 1.2.

The following examples describe the invention more (A) A composition of cetane and 0.375% by weight of clearly although the scope of the invention is not limited cupric 0,0-diisopropylphosphorodlthioate was tested, along thereto. Reference to parts or precent is on a weight basic with several co-additives. The following results were obunless otherwise specified. tamed:

TABLE I Co-addltive Wt. Ooefi. of Wear Rate,

percent Friction cc./cm. 10-

None 0.23 35.9 Pheny1hydrazine 0. 083 0. 25 0. 0863 1,4-naphtha1enedi0l 0. 183 0. 0. 191 Methylhydroquinone 0. 142 0. 29 0. 396 Tri-n-hexadeeylhydroquinone.. 0.89 0. 13 0. 132 1,4-naphthoqulnone 0. 180 0. 17 0. 322 Cetyltrimethylammonium borohydrlde 0. 190 0.333

EXAMPLES (B) The same series of tests were performed using The antiwear properties of the additives of this inven- 0.37% of nickel 0,0-diisopropylphosphorodithioate. The

tion are evaluated in the following test: following results were obtained:

TABLE II (Jo-additive Wt. Coefl. 0! Wear Rate.

percent Friction cc./cm. 10-

None (I) Methylhydroquinone 0 142 0.17 0.261 Oetyltrtmethylammonlum borohydr1de.. 0 190 0.340

I Bcufiing.

A stationary pin is held upright against axially-mounted (C) The same tests were performed using 0.325% of rotatable disc, and the disc is rotated at a constant velocchromium 0,0-diisopropylphosphorodithioate with the folity. The pin, by virtue of this rotation, describes a circle lowing results:

TABLE III (Jo-additive Wt. Goefl. oi Wear Rate,

percent Friction cc. lcm. X10- N one 1 1, 590.0 Methylhydroqulnone 0.146 0. 19 0. 466 Cetyltrtmethylammonium borohydrlde 0. 190 4. 96

l 22 minutes.

on the surface of the disc concentric with the axis thereof. (D) Mercuric 0,0-dineopentylphosphorodithioate com- Both pin and disc are contained in a vessel holding the positions were tested by the same test with the following test lubricant so the point of contact between the pin and results:

TABLE Iv (Jo-additive Wt. Goefl. 0! Wear Rate,

percent Friction cc./cm.X10-

None (0.591% mercuric salt) 0. 21 32.1 Phenylhydrazine (0.565% mercuric salt). 0. 14 3. 18

the rotating disc is lubricated at all times. The pin is (E) Silver 0,0-diisopropylphosphorodithioate was testmade of AISI 1020 steel and has a hemispherical tip. The ed in cetane by the same test with the following results:

TABLE V (Jo-additive Wt. Coefl. of Wear Rate,

percent Friction cc./cm.X10-

None (0.49% silver salt) 0. 1.48 1,4naphtha1enedi01 (0.42% silver salt) 0.183 0. 094 0. 0529 disc is also made of AISI 1020 steel and is 7.6 cm. in di (F) Lead 0,0 diisopropylphosphorodithioate was ameter. The force of the pin against the disc may be tested in cetane according to the above test with the folchanged by varying the load using the controls outside lowing results: i of the lubricant vessel. TABLE VI The lubricating compositions of this invention were 0 wt 0 tested at a load of 8 kg. using a sliding velocity of 10 cm. 0' 1 We Percent F i c t io cl'ifiiifiigtg per second. The concentration of the additives in the lubricant composition was varied as set forth in the tabulated data below. The tests were run at 9 3. 3 Q. and each v is held against the three stationary balls may be varied 6 G) 0,0-diisopropylphosphorodithioic acid was tested This invention has been described by the use of speaccording to the above test with the following results: cific examples and embodiments, however the scope of the TABLE vrr (Jo-additive Wt. Good. of Wear Rate,

Percent Friction cc./cm.X10-

None (0.326% acid) 45. 9 Methylhydroquinone (0.328% acid) 0.142 0. 24 0. 437

(H) An anhydride form of 0,0-diisopropylphosphoroinvention is not consideredto belimited thereby except dithiocic acid was tested by the same test at a concentraas described in the following claims. tion of 0.325%, with the following results: We claim:

TABLE Vin 1. A lubricant composition comprising a major amount of a lubricating oil and a minor amount of a mixture Co'addmve P212"... fiiiifiifi a of compounds consisting of: N0 7 (1) a dlorganophosphorodithioate compound having ue 0. 15.6 Methylhydroquinone 0.142 0.19 2.62 the Structure The activating agents used in conjunction with the 20 phosphorodithioates to form the synergistic mixtures of 8 this invention were tested alone in cetane at approxi- 1 ,i ,il mately the same concentrations as used in the above tests. No phosphorodithioate was present. These results are tabulated below: wherein R is a hydrocarbyl radical having from 1 Activating Agent Wt. Coeii. of Wear Rate,

Percent Friction cc./cm. X10

Methylhydroquinone 0. 142 0. 24 2. 53 Tri-n-hexadecyl hydroquinone 0. 89 0.21 1. 05 1,4-naphthalene-diol Phenylhydrezine.

1,4-naphthoquinone Cetyltrimethyl ammonium borohydride.

FOUR-BALL WEAR TEST to about carbon atoms, M is selected from the In this test, three steel balls of 52400 steel are held group conslstmg of hydrogen in a ball cup. A fourth ball positioned on a rotatable verfi fi tical axis is brought into contact with the three balls and ISP(OR)Z] SP(OR)2 is rotated against them. The force which the fourth ball and a metal and v is the valence of and (2) an organic activating agent selected from the group consisting of (a) a quinone, (b) an aromatic diol, (c) an aromatic hydrazine, and (d) an organoammonium borohydride, said (a), (b) and (c) having the structure according to a desired load. The test lubricant is added to the ball cup and acts as a lubricant for the rotation. At the end of the test, the steel balls are investigated for wear scar; the extent of scarring represents the effectiveness of the lubricant as an anti-wear agent. A number of metal 0,0-diisopropylphosphorodithioates were used in l these tests. They were combined with methylhydroquinone wherein is a hydrosai-byl radical having ir'om 1 (MHQ) as an activating agent. The tests were conducted to about 30 carbon atoms, n is in the range of O to under a load of 20 kg. at 200 F. for minutes. The to 5 and the group [--[Ar]Xm] (Ar)Xm is setational speed was 600 r.p.m. or 23.3 cm./sec. sliding lasted f the group consisting of speed. The concentration of the phosphorodithioate in the (a) a quinone in which is a quinone nucleus composition was sufficient to provide 1.5 X10 gramand m is 2 and M is selected from the atoms of phosphorus per 100 grams of sample; the meth- 55 group consisting of metal and ylhydroquinone concentration was 1.1 l0 mole per s 100 grams of sample. The lubricant carrier was cetane. The results are tabulated below: [S 0 (0 )r Additives Ave. Wear Wear Volume Ooefi. of Scar, mm. in cc. Friction Oomp.:

3. alt 1. 145 264. 0 10 0. 27

5. Zinc salt 1. 305 477.0x10- 0.27

6 Zinc salt+MHQ 0.480 7. 24x10- 0.17

It may thus be seen that the additive combinations of this invention provides unexpected improvement in the (b) an aromatic diol in which Ar is selected from antiwear properties of a hydrocarbon fluid. The composithe group consisting of phenylene and naphthyltion of this invention may contain other additives such as ene, X is OH, M is selected from the group detergents and extreme pressure agents, viscosity conconsisting of hydrogen and metal and m is 2; trolling agents, and the like, depending upon the chat'- and acteristics required for a specific utiliity. (c) an aromatic hydrazine in which Ar is selected from the group consisting of phenyl and naphthyl, X is NHNH and m is 1;

and said (d) having the structure (R" -N)BH wherein R" is selected from the group consisting of alkyl and aryl having from 1 to 20 carbon atoms, in which each R" group need not be the same as any of the others;

wherein each of said compounds of the mixture is present in sufficient amount to provide improved anti-wear properties to the lubricant composition.

2. The composition of claim 1 wherein the activating agent is a hydroquinone.

3. The composition of claim 1 wherein the activating agentis a naphthy-lene diol.

4. The compositionof claim 1 wherein the activating agent is naphthoquinone.

5. The composition of claim 1 wherein the diorganophosphorodithioate is a metal 0,0-diorganophosphorodi thioate wherein the metal is a member of the group consisting of 1B, IIB, IVA, VIB and VIII of the Periodic Table.

6. The composition of claim 5 wherein the metal is selected from the group consisting of zinc, lead, copper, silver, mercury, chromium and nickel.

7. The composition of claim 1 wherein the activating agent is an aromatic hydrazine.

8. The composition of claim 7 wherein the activating agent is phenylhydrazine.

9. The composition of claim 1 wherein the activating agent is cetyltrimethylammonium borohydride.

10. A mixture of additives contained in the lubricant composition of claim 1.

11. The mixture of claim 10 wherein the activating agent is selected from the group consisting of a hydroquinone, a naphthoquinone, a phenylhydrazine and alkyl derivatives thereof.

12. The mixture of claim 10, wherein the activating agent is cetyltrimethylammonium borohydride.

References Cited UNITED STATES PATENTS 2,234,581 3/1941 Rosen 25249.6 2,739,122 3/1956 Kennerly et a1. 25232.7 2,789,951 4/1957 Kern et a1. 25232.7 2,906,770 9/1959 Debo 25246.7 XR 2,934,499 4/1960 Goldschmidt 25232.7 2,975,136 3/1961 Thomas et a1. 252 XR 3,070,546 12/1962 Butler et a1. 25232.7 3,143,507 8/1964 Mastin et a1. 25246.6 3,318,808 5/1967 Plemich et a1. 25232.7

DANIEL E. WYMAN, Primary Examiner.

PATRICK P. GARVIN, Assistant Examiner.

U.S. C1. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,423 ,316 January 21 1969 Joseph J. Dickert, Jr. et a1 It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shmm below:

Column 2 line 7 "proyl should read propyl line 44 "napthols" should read naphthols line 46 "theerof" should read thereof Column 3 line 37 after "against" insert an- Column 5 line 70 "provides" should read provide Column 6 lines 21 and 22 the formula should appear as show below:

same column 6 lines 39 and 40 the formula should appear as shown below:

same column 6 line 48 the formula should read R n- (ArJXm line 51 [Ar]Xm] [Ar)Xm" should read (ArJXm lines 56 and 57 the formula should appear as shown below:

Signed and sealed this 24th day of March 1970 (SEAL) Attest:

EDWARD M. FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

